Method for processing, in particular casting, a material,  casting mold for carrying out the method and articles produced by the method or in the casting mold

ABSTRACT

A method for producing articles in a mold includes bringing a material into a free-flowing state, introducing the material into the mold via a bottom-casting principle, and solidifying being carried out according to a top-casting principle. The material, viewed in a flow direction of the material, is first introduced into a pouring basin of a runner, then flows through the runner, thereafter through a storage space that is located upstream from a cavity and that is arranged underneath the cavity, and from there into the cavity. Thereafter the mold including the sub-parts of the mold is pivoted so that the storage space takes over the function of a feeder or riser.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and Applicant claims priority under 35 U.S.C. §§120 and 121 of parent U.S. patent application Ser. No. 12/448,123 filed Feb. 17, 2010, which application is a national stage application under 35 U.S.C. §371 of PCT/DE2007/002176 filed Dec. 4, 2007, which claims priority under 35 U.S.C. §119 of German Application No. 10 2006 058 145.8 filed Dec. 9, 2006, the disclosures of each of which are hereby incorporated by reference. The international application under PCT article 21(2) was not published in English. A certified copy of priority German Patent Application No. 10 2006 058 145.8 is contained in parent U.S. application Ser. No. 12/448,123.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a process for processing a material which initially is brought from its solid state into a free-flowing state and forthwith introduced into a mold, in which the material is then induced to solidify. Further, the invention relates to molds for carrying out the method and to articles which are being or have been produced according to the method and/or in such molds.

2. Prior Art

Basically, there are four commonly used casting methods, mainly gravity casting methods, i.e. bottom-casting, side-casting, top-casting and tilt-casting, which, although they all have certain advantages when compared in relation to each other, they also all have certain disadvantages.

For example, bottom-casting achieves the most laminar mold filling, but the coldest material during the solidifying process is in the said feeder/riser, i.e. the storage space, from where during solidifying additional material is to be fed so that here topping-up must be ensured by providing larger feeder dimensions.

With side-casting, albeit, the material in the feeder is relatively hot, but mold filling is more turbulent than with bottom-casting.

With top-casting the hottest material is in the feeder or riser so that topping-up is good for a minimum feeder volume, but the quality of the castings deteriorates due to turbulence as a function of the filling height.

With tilt-casting, where again the hottest material is in the feeder, undesired swirls and flow lines appear on the casting surface. The contour of the casting determines the flow direction of the liquid material which, in turn, leads to overheated areas in the mold and thus also in the casting.

SUMMARY OF THE INVENTION

It is the requirement of the present invention to avoid the disadvantages of the previously known casting methods and to develop methods for processing materials which, for optimum turbulence-free laminar mold filling, also allow optimum topping-up with the hottest metal coming from a storage space thereby permitting smaller storage or feeder volumes. In addition overheating from contour-related material accumulations is to be avoided and savings are to be achieved in the cycle, material, energy, transport and machining outputs. Further, the production of large-surface and complicated castings shall be simplified and thus become cheaper. A further requirement aspect consisted in the creation of respective casting molds for the cost-effective and high-quality production of castings.

According to the invention the process for processing materials by bringing the same into a free-flowing state and introducing them into a mold is initially characterised in that introducing into the mold is carried out according to the principle of bottom-casting and solidifying is carried out according to the principle of top-casting. In other words, the material is initially brought into a free-flowing state by heating and introduced into a casting mold or into the hollow space or cavity of the mold according to the principle of bottom-casting, and solidifying is carried out according to the principle of top-/tilt-casting.

Introducing the material into the cavity of the casting mold is carried out from the bottom through a pouring run, as is common for bottom-casting, by initially introducing the melt from the top into a pouring basin higher, at least in part, than the cavity, from there through a downwardly directed inflow, then upwards via a bend—the inlet—into a storage space situated below the cavity and through the outlet thereof into the cavity, and solidifying then takes place with the storage space at the top, as is common for top-casting, by pivoting the mold prior to solidifying the material so that the storage space now assumes the function of the feeder/riser.

In order to avoid spilling out of the melt from the pouring basin during pivoting and thereafter, it may be advantageous if a slide arranged in the pouring run in front of the cavity—when viewed in flow direction of the melt—is activated in good time prior to or during pivoting of the mold.

Alternatively, instead of a slide a closure may be provided on top of the pouring basin, which closure is activated prior to pivoting.

It is convenient if the mold is pivoted about an axis which extends, at least approximately, in parallel to the separating-groove plane or separating-groove planes of the mold.

Furthermore, it may be of advantage if the cavity and the pouring run and thus also the separating-groove(s) or separating-groove(s) plane(s) are provided or arranged at an angle to each other. Either the pouring run or the cavity may extend obliquely, or both the cavity and the pouring run may be arranged at an oblique angle to the horizontal, whereby cavity and pouring run may enclose a blunt angle between them. But it is also possible for cavity and/or pouring run to extend at a shallow angle in relation to the horizontal.

It may be particularly advantageous if cavity and pouring basin are arranged at such an angle to each other and are jointly pivoted about such an angle and in such a direction that, when reaching a position of the storage space where the storage space can assume the function of the feeder or riser, the pouring run has not yet reached the horizontal, whereby it is especially advantageous if pivoting of the mold is carried out in a direction such that the pouring run is leading so that in the solidifying position the pouring run points upwards, at least slightly, thus making it impossible for the melt to spill out from the storage space which, as already mentioned, then acts as a feeder or riser.

A further development of the invention relates to a casting mold or ingot mold which below the cavity has a storage space into which the pouring run leads, whereby the area of the pouring run leading into the storage space has a portion—the inlet—, which lies lower than the storage space.

The casting mold may further be characterised in that the cavity and the pouring run are provided not so as to extend in parallel to each other, but at an angle to each other. The casting mold or ingot mold may be shaped in such a way that both, i.e. cavity and pouring run, are inclined, possibly forming a blunt angle in relation to each other. The angle may be chosen such that when the mold is pivoted into a position in which the storage space comes to lie above the cavity—i.e. the solidifying position—and the storage space is able to act as feeder or riser, the pouring run finds itself in a position where spilling out of melt from the storage space is avoided, in that the storage space, at least with a part of it, projects at least slightly upwards in relation to the horizontal. It is advantageous if the pouring run is shaped in such a way that cavity and pouring run are arranged relative to one another in such a way and the mold is pivoted in such a way that the pouring run is leading.

The pivotable casting mold where the mold halves surrounding both the pouring run and the storage space as well as the cavity are separated from each other by respective separating-grooves is conveniently shaped in such a way that pivoting is carried out about an axis which, at least approximately, extends in parallel to the plane of the separating-groove plane.

This casting mold—with the storage container at the bottom—is fillable with melt according to the bottom-casting principle, whereby the storage space lies below the cavity and solidifying of the melt is carried out within the pivoted casting mold—with the storage space then acting as feeder or riser now at the top.

In order to avoid the melt from spilling out during or after pivoting it may also be advantageous if the casting mold comprises a closure on top of the pouring basin or a slide in the area of the pouring run, whereby closure or slide are activated prior to, or in good time during pivoting.

Moreover the invention relates to casting products being or having been produced by the inventive method and/or by means of the casting molds according to the invention, whereby these casting products produced by the gravity-casting method in an especially convenient and advantageous manner consist of light-metal alloys such as, in particular, aluminum alloys.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained further with reference to the FIGS. 1 to 9.

FIGS. 1 to 4 show traditional prior art casting methods and FIGS. 5 to 9 show the casting method according to the invention.

FIG. 1 schematically shows the casting method using so-called bottom-casting,

FIG. 2 shows the casting method using side-casting,

FIG. 3 shows the casting method using top-casting.

FIG. 4 shows the casting method using tilt-casting.

FIG. 5 shows a first step of the method of the invention.

FIG. 6 shows a second step of the method according to the invention.

FIG. 7 shows an intermediate position of the mold of FIG. 5 after the mold has been pivoted by approximately 90°.

FIG. 8 shows another mold according to the invention with parts arranged at a blunt angle to each other.

FIG. 9 shows the mold of a FIG. 8 after pivotation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 1 to 4 the casting mold or ingot mold is designated 1A, 1B, 1C and 1D respectively and the hollow space of the mold or the cavity is designated 1 a to 1 d respectively.

In each of FIGS. 1 to 4 a feeder or riser 2 a to 2 d is provided from which so-called topping-up may be carried out while the cast is solidifying.

With bottom-casting, side-casting and top-casting according to FIGS. 1 to 3 the casting molds stand upright and in FIGS. 1 and 2 the melt is introduced via the pouring basins 4 a, 4 b. With top-casting according to FIG. 3 and with tilt-casting according to FIG. 4 the riser 2 c, 2 d also acts as pouring basin. With tilt-casting according to FIG. 4—in the example shown here—the melt is initially introduced into the container 2 d′ with the ingot mold 1D in a horizontal state, and the mold 1D is pivoted in the direction of arrow 3, the melt flows through the feeder 2 d until the ingot mold stands upright, and in this position solidifying of the material takes place with the feeder 2 d at the top.

With bottom-casting and side-casting according to FIGS. 1 and 2 the material is initially fed via grey-shaded pouring run 5 a, 5 b respectively, into the pouring basin and from there into the cavity 1 a, 1 b. With bottom-casting according to FIG. 1 the pouring basin 4 a is connected to inlet 6 which becomes an inlet area 7 which in this case lies lower than cavity 1 a, and the melt enters cavity 1 a through outlet 8.

It can be seen that in bottom-casting according FIG. 1 a filling of the mold is achieved which is at its most laminar.

With side-casting according to FIG. 2 the mold is filled by excessively raising the bath level in the outlet in the hollow space of the mold, and the filling is thus less laminar than with bottom-casting.

With top-casting according to FIG. 3 mold filling is at its most turbulent leading to a greater enrichment of the melt with oxides, gas bubbles and foam.

With tilt-casting according to FIG. 4 distinct flow lines appear. Additionally the flow direction of the material is determined by the contour of the casting and as a consequence, leads to overheated areas in the mold which in turn give rise to faults in the casting.

With casting by the tilt-casting method according to FIG. 4 and the top-casting method according to FIG. 3, the hottest material is always in the feeder, which results in optimum topping-up, but the mold is filled, not in the desired laminar, but in a turbulent manner.

With bottom-casting according to FIG. 1, as already mentioned, mold filling is at its most laminar, with side-casting according to FIG. 2 the result as regards laminar filling is less good, and both casting methods, i.e. bottom-casting and side-casting suffer from the disadvantage that the coldest material is in the feeder or riser so that during solidifying larger feeders are a must in order to achieve optimum topping-up.

With the present invention which will now be explained in more detail with reference to FIGS. 5, 6 and 7 the advantages of bottom-casting and side-casting, that is optimum laminar mold filling, are combined with the advantage that during solidifying the hottest metal is in the feeder.

As shown in FIG. 5 filling of the casting mold indicated by 1E is practically the same as in FIG. 1, that is by the bottom-casting method, with the melt reaching cavity 1 e by passing through pouring run 5 c also shown grey-shaded. The melt filled into pouring basin 4 e flows to the bottom through inflow 6 a, through the area extending below a storage space 9 in this case, through inlet 7 a, through storage space 9 and from there through outlet 8 a of storage space 9 into cavity 1 e. Prior to solidifying the material, for example as a function of a certain temperature, the whole casting mold 1E is pivoted as illustrated in FIG. 6, here by approximately 180° about axis I corresponding to rotating direction II. This causes storage space 9 to be at the top so that this storage space 9 is now acting as a feeder or riser until the material has solidified.

FIG. 7 shows a position of the casting mold or ingot mold 1E after it has been pivoted by approximately 90° from its position in FIG. 5. In this figure the separating groove 10 between the two mold halves 1E′ and 1E″ can be seen and also the pivoting axis I which extends in parallel to and through the plane formed by the separating grooves 10. FIG. 7 also shows the face of cavity le and the face of storage space 9 as well as the inlet 7 a and the pouring basin 4 e.

In many cases it will not matter whether in the position of FIG. 6 melt spills out of pouring basin 4 e, inflow 6 a or inlet 7 a, since by then the melt present in there is no longer needed for the subsequent phases of the casting process.

It may be convenient if the ingot mold 1E is moved quickly between the position it occupies shortly before it reaches the position shown in FIG. 7 and a position shortly thereafter, so that it is practically not possible for melt to spill from the cavity and the storage container. In the area of the pouring basin 4 e however, a closure 11 may be provided, or a slide 12 in the area of the inflow, which are activated in good time before or during pivoting, so that the pouring run is closed there.

Alternatively pivoting may be effected about an axis other than the horizontal axis or an axis extending, at least approximately, in parallel to the plane of the separating groove 10, for example about axis III extending, at least approximately, perpendicularly thereto. It can be advantageous if pivoting is effected in direction of arrow III′ so that the pouring run or the pouring basin is leading and melt cannot spill out from the same until the storage container 9 has at least reached a position where it is at the top. But pivoting may also be effected about other axes than the axes and curves illustrated, for example about axes or curves which are a combination of those shown; where a closure or slide is used the rotating direction is less important as regards the escaping of melt from the pouring run.

In FIGS. 8 and 9 cavity 20 and at least parts of pouring run 21, i.e. inflow 22, are arranged at an angle to each other, in this case at a blunt angle.

Again one can recognize pouring basin 23 and bent inlet 24 which leads into storage space 25, and that the latter changes via an outlet 26 into the cavity. Cavity 20, storage space 25 and inlet 24 may be arranged in relation to each other such that inlet 24 lies lower than storage space 25 and this, in turn, lies lower than cavity 20. But it may also be advantageous or sufficient in some cases if inlet 24 is not arranged below storage space 25. In FIGS. 8 and 9 cavity and inflow, as already mentioned, are provided to extend at a blunt angle 26 in relation to each other and both enclose an angle 27 and 28, respectively, in relation to a plane 29 which extends, at least approximately, perpendicularly to the horizontal.

After introducing the melt and in good time before the same solidifies, mold 30 is pivoted into the position shown in FIG. 9, i.e. about axis 31 which extends, at least approximately, in parallel to separating groove 32 of mold 30, i.e. conveniently in a pivoting direction of arrow 33 so that pouring run 21 with pouring basin 23 are leading until in a position in FIG. 9, in which cavity 20 is brought Into such a position that storage space 25 is now above cavity 20 and can assume the function of a feeder or riser. In the viewpoint shown in FIG. 8, axis 31 projects at a 90° angle into and out of the plane of the paper (at the center of the sign + shown in FIG. 8) and the separating groove 32 also projects at a 90° angle into and out of the plane of the paper.

Pivoting here has reached a point, where inflow 22 has not quite yet reached horizontal 34, therefore no melt or only very little melt can spill out.

It can be seen that the method according to the invention or that the casting molds according to the invention make it possible to carry out casting according to the bottom-casting principle with optimum laminar mold filling compared to other casting methods and to effect solidifying according to the top-casting principle which, again, results in the best possible topping-up.

The invention further relates to casting molds which are produced by the method according to the invention and/or in the casting molds according to the invention. Although the method according to the invention is especially suitable for the processing of light-metal, in particular light-metal alloys such as aluminum alloys, the invention is not limited to the use of light-metal alloys but other materials, such as also non-metallic materials, can be processed according to the invention.

LIST OF REFERENCE SYMBOLS

-   1A to 1E casting mold -   1 a to 1 e cavity -   2 a to 2 d feeder/riser -   2 d′ container -   3 arrow -   4 a to 4 e pouring basin -   5 a,5 b,5 c pouring run -   6 inflow -   7, 7 a inlet -   8, 8 a outlet -   9 storage container -   I axis -   10 separating groove -   1E ingot mold (casting mold) -   1E′, 1E″ mold halves -   11 closure -   12 slide -   20 cavity -   21 pouring run -   22 inlet -   23 pouring basin -   24 inlet -   25 storage space -   26 angle -   27, 28 angles -   29 horizontal plane -   30 mold -   31 axis -   32 separating groove -   33 pivoting direction 

What is claimed is:
 1. A casting mold or ingot mold for carrying out a method for casting a material by bringing the material into a free-flowing state by heating and introducing the material into the casting mold or ingot mold according to a principle of gravity casting, said casting mold or ingot mold comprising a runner with a pouring basin, a storage space attached to the runner as well as a cavity attached thereto with a downsprue, wherein the storage space is arranged underneath the downsprue of the cavity and wherein the casting mold can be pivoted together with pouring basin, runner, storage space and cavity.
 2. The casting mold according to claim 1, wherein the runner leading into the storage container comprises a portion which lies lower than the storage container.
 3. The casting mold according to claim 1, wherein the cavity and the runner are provided at an angle relative to each other.
 4. The casting mold according to claim 1, wherein both the cavity and the runner are arranged at an angle in relation to a plane extending between them, which plane extends, at least approximately, perpendicularly to the horizontal.
 5. The casting mold according to claim 3, wherein cavity and runner are provided at a blunt angle relative to each other.
 6. The casting mold according to claim 1, wherein cavity and runner are provided at such an angle relative to each other that, when the mold is pivoted into a position in which the storage space comes to lie above the cavity—i.e. the solidifying position—and the storage space can act as feeder or riser, the runner finds itself in a position in which spilling out of the liquid casting substance from the storage space is avoided.
 7. The casting mold according to claim 6, wherein the runner, in the solidifying position, points obliquely upwards relative to the horizontal.
 8. The casting mold according to claim 1, wherein cavity and runner are arranged relative to each other in such a way that the mold can be pivoted such that the runner is leading.
 9. The casting mold according to claim 1, wherein two mold halves surrounding both the runner and the storage space as well as the cavity are separated from each other by separating grooves and the casting mold is pivotable about an axis which, at least approximately, extends in parallel to its separating-groove plane.
 10. The casting mold according to claim 1, wherein the mold—with the storage container at the top—can be filled with melt according to the bottom-casting principle and wherein the mold is pivotable and solidification of the melt is effected with the storage space acting as feeder or riser at the top.
 11. The casting mold according to claim 1, wherein a closure is provided on top of the pouring basin.
 12. The casting mold according to claim 1, wherein a slide is provided in the area of the runner.
 13. A casting product, wherein it consists of a light-metal alloy, such as in particular an aluminum alloy manufactured according to claim 1 by the gravity method.
 14. A method for casting a cast part from a metal melt comprising the following steps: a) providing a rotatably-mounted casting mould comprising a mould cavity shaping the cast part, a feed system for feeding the mould cavity with metal melt and a pour channel, via which the feed system can be filled with metal melt, wherein the feed system is arranged in relation to the mould cavity of the casting mould so that when the casting mould is rotated into a fill position the filling of the mould cavity with the metal melt takes place via the feed system against the acting direction of gravity, and wherein a filling opening, provided for filling the metal melt, of the pour channel is arranged on a lateral side of the casting mould remotely from a mouth of the pour channel into the feed system so that the filling opening of the pour channel is arranged in the respective fill position of the casting mould above the mouth of the pour channel into the feed system; b) aligning the casting mould in a fill position in which metal melt filled in the pour channel as a consequence of the effect of gravity flows through the pour channel, wherein the main flow direction of the metal melt makes an angle relative to the acting direction of gravity; c) filling the casting mould aligned in the fill position with the metal melt, until the casting mould, including the pour channel, is completely filled with metal melt; d) rotating the casting mould into a solidification position, in which as a result of the effect of gravity the melt present in the feed system is pushed against the melt present in the mould cavity; e) holding of the casting mould in the solidification position until the metal melt present in the casting mould has reached a certain solidification state; f) de-moulding of the cast part.
 15. The method according to claim 14, wherein in connection to step c), the casting mould is sealed with a stopper placed in the filling opening of the pour channel, whereby rotating in step d) then takes place with a sealed casting mould.
 16. The method according to claim 14, wherein an axis of rotation of the casting mould is aligned horizontally.
 17. The method according to claim 14, wherein the pour channel of the casting mould runs linearly.
 18. The method according to claim 14, wherein the filling opening of the pour channel is allocated to an underside of the casting mould.
 19. The device according to claim 1, wherein the axis of rotation of the casting mould is aligned horizontally. 